This study demonstrates that in in vivo models and patients with rheumatoid arthritis the effects of antiinflammatory drugs, specifically methotrexate and sulfasalzine, are due to their capacity to increase extracellular adenosine. The investigators have concluded that signal transduction of adenosine proceeds by a novel pathway. The lab was used for the following: ELISA, oligonucleotide synthesis Northern analysis and PCR.